1. Field of the Invention
The present invention relates to a light source of a non-self-luminous display device, and more particularly to a liquid crystal display device having a backlight which includes LEDs (light emitting diodes) as a light source.
2. Background Art
Recently, the liquid crystal display device has been popularly used as a display device. Particularly, the liquid crystal display device is used as a display part of portable equipment because the liquid crystal display device is thin and light-weighted and consumes small electric power.
However, the liquid crystal display device is not self-luminous and hence, the liquid crystal display device requires a lighting means. In general, as a lighting device of the liquid crystal display device, a planar lighting device referred to as a backlight is popularly used. Conventionally, although a cold cathode fluorescent lamp has been used as a light emitting element (also referred to as a light source) of the backlight, a light emitting element which uses LEDs has been also recently used for a portable equipment.
In a liquid crystal display device which uses LEDs as a light source, there has been proposed the constitution which takes the heat radiation into consideration. For example, JP-A-2003-281924 or the like discloses the structure in which LEDs and a box-shaped metal casing are adhered to each other. Further, JP-A-2006-235399 also discloses the structure in which a heat-conductive sheet is packed in a space around LEDs.